Unless you want to play your local FNM with a half-English / half-Japanese Standard deck, non-English cards are just too much of a hassle for the average player to sell to make buying a Japanese box worth it when you consider you won't really open that many alt-art planeswalker in your box and there's a very real chance you miss on the best of the bunch, especially for double the English price
Hand of Vecna's triggered ability uses the number of cards in your hand as it resolves to determine the bonus the creature gets
Ixalan (2017) has four new ways to draw cards, three of which are again new versions of old themes, none of which we see that much in the larger picture
The power of Reflecting Pool really depends on your own land cards, but it can actually be very versatile in mana fixing
Finally, Errant just seemed like a plain misfire, even when it came out
Choose Counter Intelligence if you are a brewer at heart